Changes in soil organic matter composition after afforestation of arable farmland in northeast China. Issue 3 (15th March 2016)

• Record Type: Journal Article
• Authors: Cong, Weiwei; Ren, Tusheng; Li, Baoguo
• Is Part Of: Chemistry and ecology. Volume 32:Issue 3(2016)
• Page Start: 201
• Page End: 220
• Publication Date: 2016-03-15
• Subjects: Afforestation -- chemical composition -- SOC content; Pollution -- Environmental aspects -- Periodicals; Ecology -- Periodicals; 577.2
• DOI: 10.1080/02757540.2015.1133612
• Languages: English
• ISSNs: 0275-7540

Abstract

ABSTRACT: Since the 1970s, a substantial area of arable farmland in a semi-humid area of northeast China has been planted as deciduous forests ( Populus tomentosa Carr.). This study investigates the effects of afforestation on soil organic carbon (SOC) content and the chemical composition of the soil. Soil samples ( Calcic chernozem ) were collected from the upper 10 cm of paired arable land and secondary forests established 5 and 25 years previously. Carbon isotope analysis and pyrolysis–gas chromatography/mass spectrometry were used to determine SOC composition. The results show that (i) compared to the arable land, five years of afforestation caused a decrease in SOC and N concentration, while 25 years of afforestation resulted in an increase in SOC content; (ii) stable isotope δ 13 C analyses of the forest soils show gradual loss of crop-derived C and an accumulation of forest-derived C; and (iii) afforestation increased lignin abundance and decreased decompositional activity in the 25-year-old forest topsoil. Higher amounts of short-/mid-chain aliphatic compounds were observed in the 5-year-old forest (5–10 cm); and (iv) the arable soil contained substantially higher amounts of decomposed plant material and microbially derived substances. The results obtained suggest that long-term afforestation increases the SOC concentration, and alters the chemical composition of SOC.